The measure of how many new infections a single COVID-19 infection will produce has now dropped to around 1 in King County, with similar trends observed in Snohomish and Pierce counties, according to a Tuesday news release from the State Emergency Operations Center at Camp Murray, home of the Washington National Guard in Tacoma. The distancing efforts, including Gov. Jay Inslee’s Stay Home, Stay Healthy order, must remain in place to prevent a rebound in the number of cases and deaths.

“We know the sacrifices and uncertainty families, businesses, schools and communities across Washington have faced. This new report confirms that working together through this crisis with unwavering commitment is slowing this serious disease,” said Dr. Kathy Lofy, Washington State Health Officer. “Our collective efforts are working, but we can’t let up our guard.”

Bellevue-based Institute for Disease Modeling (IDM) developed the report, analyzing similar data to its previous forecast for King County. This new data provides enhanced results from previous virus transmission models reported from IDM that analyzed the overall “mobility” of people in King County, both before and after physical distancing policies were announced. Using anonymized mobility data from the two previous reports, IDM researchers found COVID-19 transmission measures continued to decline for the most recent report.

While the report and other data are encouraging signs and will help guide policy decisions, any modifications to stay at home orders will need to happen gradually to ensure we don’t see a rebound of disease activity, according to the news release. On Monday, Inslee and the governors of California and Oregon announced an agreement on a shared vision for reopening their economies and controlling COVID-19 into the future.

County health officials and IDM applauded the efforts of Washington residents, businesses and governments to prevent the spread of the disease and stressed the need for those efforts to continue:

Jeff Duchin, Health Officer, Public Health – Seattle & King County: “The social distancing steps the public has taken are having a real impact in reducing the spread of COVID-19 in our region. Now is not the time to relax – we need to continue with the current measures and further decrease transmission. The threat of a rebound that could overwhelm the healthcare system remains if we let up too soon.”

Anthony L-T Chen, MD, MPH, Director of Health, Tacoma-Pierce County Department of Health: “Based on the number of positive cases, 99 percent of Pierce County residents have not gotten COVID-19 and have no immunity. We really appreciate that people are staying home and slowing the spread of disease, but we must keep it up and not let our guard down.”

Chris Spitters, Health Officer, Snohomish Health District: “Now is not a time to celebrate, but to humbly take stock in what we appear to have achieved so far. Our hospital systems, healthcare partners and first responders are relying on of all us as a community to sustain the focus, discipline and patience it will take to get to the other side of this pandemic.”

Mike Famulare, Principal Research Scientist, IDM: “It’s encouraging that social distancing measures are working better than we initially estimated, but we are at a critical point in our pandemic response and must not relax current measures or we will lose hard-fought ground.”